||The objective of this project is to develop a knowledge-based system for the minimization of environmental problems in process industries (MEPPI). Four major process industries - the metal finishing, printed circuit board manufacturing, micro-electronics and printing & dyeing industry - in Hong Kong were investigated intensively. MEPPI is designed to assist process engineers and management to minimize the release of hazardous and toxic materials into the environment by implementing waste minimization strategies. The constituents of MEPPI consist of a main program, a database and three knowledge bases. The main program is written under an object oriented programming tool called Kappa-PC. Most objects such as chemicals and process units are represented by object-attribute-value triplet while the knowledge and expertise acquired through industrial visits and literature are represented by a set of rules. There are three major kinds of information of which MEPPI requires : inventory, process streams and process units. According to this information, processes can be modeled and all information can be inferred to obtain valuable recommendations on the issues of minimizing hazardous waste generation. Besides offering recommendations on minimizing hazardous waste generation, effluent concentrations from the process will also be compared with the local discharge standards (in Hong Kong it is the TM Standard) and the outraging items will be highlighted as well. Lastly, an optical frame manufacturer and a PCB manufacturer had been invited to study the applicability of MEPPI in real situations. The recommendations offered by MEPPI have been recognized by the industries. Moreover, MEPPI had also been evaluated by government sectors and industrial users in an introductory seminar, demonstrating the applicability and usefulness of the program. From the results of the questionnaire obtained in the workshop, MEPPI was graded as good and very useful.